1. Technical Field
The present invention relates generally to mobile communication systems and, more particularly, to general packet radio services for delivering data over a circuit switched telephone network.
2. Description of the Related Art
The general packet radio service (GPRS) is a non-voice value added service that allows information to be sent and received across a mobile telephone network. It supplements, or rides on top, of today's circuit switched data and short message service networks. The theoretical maximum speed of GPRS includes speeds of up to approximately 171.2 kilobits per second (kbps). This maximum speed is achievable in GPRS systems using all eight timeslots at the same time in a time division multiple access (TDMA) context.
This speed is about three times as fast as data transmission speeds possible over today's fixed telecommunication networks and ten times as fast as current circuit switched data services on Global System for Mobile Communications (GSM) standard time division multiple access (TDMA) networks. Thus, GPRS systems are advantageous in that they require less system resources to transmit a fixed amount of data in comparison to using a traditional circuit switched approach. By allowing information to be transmitted more quickly, immediately, and efficiently, across the mobile network, GPRS may well be a relatively less costly mobile data service compared to short message service (SMS) and circuit switched data services.
GPRS also facilitates instant connections in which information can be sent or received immediately as the need arises, subject to radio coverage. No dial up modem connection is necessary. GPRS, similar to some broadband connections for personal computers, often is referred to as being “always connected”. Thus, another one of the advantages of GPRS is that data may be transmitted immediately, whenever the need arises. In contrast to circuit switched data networks in which a connection must be established to transmit a data packet or data file, GPRS operation is extremely efficient in those situations in which a small amount of data is to be sent.
As the emphasis of many designs today are to create wireless computer networks, and to connect data devices including personal computers to wireless transceivers and mobile terminals, such a system that provides instantaneous response is very important for time critical applications, and, more generally, for the implementation of wireless computer networks.
For example, a remote credit card authorization system implemented in a wireless network can be greatly improved if it is unnecessary for the customer to wait the amount of time that is required to establish a connection. Anyone that has waited at a cash register for credit authorization while a modem dials in and transmits account information can readily appreciate this advantage.
Additionally, GPRS facilitates the use of Internet applications not only from personal computers, but also from appliances and machines. It is anticipated that appliances will be designed to be coupled to the Internet to facilitate control either onsite or remotely. While some people envision connecting these appliances to a network port by physical lines, it would clearly be advantageous to be able to connect such appliances to the Internet through a wireless link. GPRS will facilitate the creation of Internet controlled appliance networks through a wireless medium.
As suggested before, GPRS involves overlaying a packet based air interface on an existing circuit switched wireless network. For example, the circuit switched wireless network may comprise a GSM network. Accordingly, the user is given an option to utilize a packet based data service. In order to overlay a packet based air interface over a circuit switched network, the GPRS standard defines new infrastructure nodes to minimize the impact to existing networks in terms of hardware and software.
One advantage of GPRS is that the packet switching that results from the infrastructure nodes allows the use of GPRS radio resources only when users actually are sending or receiving data. Unlike traditional circuit switched voice networks, a connection is not continuously reserved for a user for the intermittent transmission of data. This efficient use of scarce radio resources means that larger number of GPRS users To can share the same bandwidth and be served from a single base station or cell. The actual number of users, of course, that may use the system at one time depends on the amount of data being transferred.
A delivery network, for example, either a Universal Mobile Telecommunications System (UMTS) network or a GPRS network, is one that provides connectionless or connection-oriented push services. A push service is the delivery of data or multimedia information from a network node to user equipment for the purpose of activating the user equipment or for providing information from the network. A push service also can include activating a packet data protocol (PDP) context, if necessary. Examples of delivery networks that offer push services include, as stated, the GPRS network, but can also include other equipment, such as a session initiation protocol (SIP) proxy, a push proxy or a short message service (SMS) service center. New services and features being contemplated require that push capabilities be implemented to enable external Internet protocol networks to deliver data to third generation wireless terminals in the paging system (PS) domain.
Some specifications allow operators to provide push services by using static IP addresses or by having long lasting PDP context. However, it would be advantageous to also provide push services within systems that utilize dynamic IP addressing schemes. In other words, push services should be provided to any mobile terminal regardless of whether it has a static or dynamic IP address. In order to use dynamic IP addresses, however, it is necessary for the network to be able to initiate a PDP context for a mobile subscriber.
In GPRS and UMTS networks, however, a network-initiated PDP context activation is not practical unless a static IP address is allocated for the subscriber. The use of static IP address assignments is cumbersome, however, because it wastes available address space for mobile subscribers that are inactive. Thus, it is desirable to initiate PDP context activation with dynamic address assignments. One problem, however, with having network initiated PDP context activation with dynamic address assignment is that a push server is likely to time out prior to the completion of the network initiated PDP context activation because of the all the steps that must be followed in a dynamic address environment.
There is a need, therefore, for a system and method that provides for push services in a dynamic IP address environment.